This invention relates in general to call routing, and more particularly to routing a voice mail call between an adjunct network element, such as a service node, and a voice mail system.
Some call management services provide a xe2x80x9crevert to voice mailxe2x80x9d feature. For example, call screening plans allow a subscriber to screen incoming calls. The subscriber is typically provided with information about the call, such as the calling number and/or the name of the calling party. Based upon the calling number and/or the name of the calling party, the subscriber can decide whether to answer the call or to allow the call to be directed to the subscriber""s voice mail.
Other call management services also provide a revert to voice mail feature. For example, call forwarding services allow a subscriber to specify that a call placed to the subscriber""s directory number be forwarded to another number if the subscriber cannot be reached using the subscriber""s directory number. If the call is unanswered at both numbers or if both numbers are busy, then the call is routed to the subscriber""s voice mail.
Call management services that provide a revert to voice mail feature typically use a service node (xe2x80x9cSNxe2x80x9d) to originate a call to the subscriber""s voice mail. To route the call to the subscriber""s voice mail, subscriber information is maintained on the SN. The subscriber information associates a voice mail access number with a subscriber""s directory number. Once a call is received by the SN, the SN determines the voice mail access number that is associated with the subscriber by accessing the subscriber information. The SN originates a call using the voice mail access number and then outputs the voice mailbox number for the subscriber using a tone generation circuit.
A disadvantage of maintaining subscriber information on the SN is that not all SN""s support the storage of subscriber information. Typically, an SN that supports the storage of subscriber information is more complex and more expensive than an SN that does not support the storage of subscriber information. In addition, if only some of the SN""s in the telephone network support the storage of subscriber information, then calls to voice mail must be routed through the SN""s that contain the subscriber information. If an SN that contains subscriber information goes out of service, then it may not be possible to route a call to voice mail because the subscriber information may not be otherwise available. Therefore, there is a need for a system and method for routing a call to voice mail that does not require the storage of subscriber information on the SN.
Another disadvantage of the current method includes the requirement for a tone generation circuit on the SN. A tone generation circuit is required on the SN to output the voice mailbox number. The SN outputs the voice mailbox number because the call integration information does not unambiguously identify the voice mailbox of the subscriber. The call integration information is sent to the voice mail system (xe2x80x9cVMSxe2x80x9d) via a Simplified Message Desk Interface (xe2x80x9cSMDIxe2x80x9d). The call integration information is ambiguous because the call integration information is not consistently derived. In some instances, the call integration information is derived from the original called party number. In other instances, the call integration information is derived from the last redirecting party number which is affected by any previous call forwarding. Because the call integration information is not consistently derived, the call integration information cannot be relied upon to identify the subscriber""s voice mailbox. Thus, there is a need for a system and method for routing a call to voice mail where the call integration information can be used to identify the subscriber""s voice mailbox so that a tone generation circuit is not required on the SN.
The present invention meets the needs described above by providing a system and method for routing a call to voice mail that does not require maintaining subscriber information on the service node. The subscriber information is maintained in a database associated with the service control point instead of in a database in the service node. The present invention also eliminates the need for a tone generation circuit on the service node to output the voice mailbox number because the call integration information can be used to identify the subscriber""s voice mailbox.
A call is received by a service node (xe2x80x9cSNxe2x80x9d) or other intelligent peripheral as part of a call management service, such as call screening or call forwarding. The SN determines whether a call should be originated to the voice mail system (xe2x80x9cVMSxe2x80x9d). If a voice mail call is originated by the SN, the SN sends a message including an access code and a subscriber identifier to the service switching point (xe2x80x9cSSPxe2x80x9d). The access code identifies the call as a voice mail call. The SSP uses the subscriber identifier to query the service control point (xe2x80x9cSCPxe2x80x9d) for routing information. The SCP determines the voice mail access number associated with the subscriber using a database associated with the SCP. The SCP responds to the SSP by providing the voice mail access number associated with the subscriber and setting the original called party number and the last redirecting party number to the directory number of the subscriber. By setting both the original called party number and the last redirecting party number to the directory number of the subscriber, the voice mailbox of the subscriber is unambiguously identified. The SSP completes the call from the SN to the voice mail system using the routing information provided by the SCP. The SN is not required to output the voice mailbox number for the subscriber.
In one aspect of the invention, the query to the SCP from the SSP includes two query messages, an INFO_ANALYZED query message and a TERMINATION_ATTEMPT query message. The SCP responds to the INFO_ANALYZED query message with an ANALYZE_ROUTE response message and responds to the TERMINATION_ATTEMPT query message with a FORWARD_CALL response message. In another aspect of the invention, the query to the SCP from the SSP is a single query message, such as an INFO_ANALYZED query message. The SCP responds to the INFO_ANALYZED query message with a response message, such as an ANALYZE_ROUTE response message. Alternatively, other types of query messages and response messages can be used to communicate to the SCP that the call is a voice mail call for the identified subscriber and to communicate the voice mail access code from the SCP.
These and other aspects, features and advantages of the present invention may be more clearly understood and appreciated from a review of the following detailed description of the disclosed embodiments and by reference to the appended drawings and claims.